This invention relates to a lubricating oil supply device for internal combustion engines and more particularly to an improved lubricating system for engines of the two-cycle type.
In the simpliest form of lubricating two-cycle internal combustion engines, lubricant is mixed by the operator with the fuel in a predetermined ratio and the lubricant fuel mixture is supplied to the engine for lubrication and running. Although this type of arrangement offers extreme simplicity, the ratio of lubricant to fuel is not ideal for all running conditions, it provides some inconvenience for the operator and it runs the risk that the operator will forget to add lubricant to the fuel and may damage the engine. In order to obviate some of these problems, it has been proposed to provide a system wherein fuel and lubricant are each supplied to the engine from separate reservoirs and in ratios which offer the opportunity of control for specific running conditions. For example, in my copending application entitled "lubricating System For Two-Cycle Internal Combustion Engine", Ser.. No. 660,748, filed Oct. 15, 1984, and assigned to the assignee of this application, there is disclosed a system of this general type. As disclosed therein, a flow sensor is incorporated for sensing the amount of fuel flowing to the engine and the lubricant is supplied to the fuel line in a proportion dependent upon the fuel flow. Although such devices have considerable advantage, they necessitate the use of fuel flow detectors, and other electronic components for measuring and supplying the appropriate amount of lubricant.
It is, therefore, a principal object of this invention to provide an improved and simplified for supplying lubricating oil for an internal combustion engine.
It is another object of this invention to provide a separate lubricating system for an internal combustion engine wherein the amount of lubricant added to the fuel is controlled in response to the fuel flow in a simplified and yet effective manner.
A disadvantage with the use of separate lubricating systems of the type described is that the quantity of lubricant in the lubricant supply tank may be depleted before the fuel in the fuel storage tank is depleted. If this happens and the engine is continued to be operated, there can be a danger of seizure or other damage. Devices have been proposed that will discontinue or reduce the amount of fuel flow when the lubricant becomes depleted, however, such devices have been very complicated and have, for the most part, relied upon electrical sensing and control devices.
It is, therefore, a further object of this invention to provide a lubricant supply system for an internal combustion engine wherein the fuel flow is also controlled in response to the lubricant control.
It is a yet further object of this invention to provide an improved and simplified arrangement for discontinuing or restricting the fuel flow in the event the lubricant becomes depleted.